Epoxy resin composition containing para, para&#39; diamino diphenylmethane



United States Patent EPOXY. RESIN COMPOSITION CONTAINING PARA,

PARA DIAMINO DIPHENYLMETHANE Jerome L. Formo, Lionel H. Le Gault, Luther L. Bolstad, and Arthur D. Sinning, Minneapolis, Minn., assignors to Minneapolis-Honeywell Regulator Company, Minneapolis, Minm, a corporation of Minnesota No Drawing. Application August 25, 1952, Serial No. 306,306

21 Claims. (Cl; 260-37) This invention relates to resin-containing molding compositions including epoxy ether condensation polymers having the following structure wherein It stands for a number (such as l, 2, 3, etc.) and R stands for the divalent hydrocarbon radical of a dihydric phenol [such as mononuclear phenols like catechol, resorcinol and hydroquinone or polynuclear phenols like bis-(4-hydroxyphenyl)-2,2-propane (bis-phenol), 4,4-dihydroxy benzophenone, bis-(4-hydroxyphenyl)-1,- l-ethane, bis-(4-hydroxyphenyl)-1, l-isobutane, bis-(4- hydroxyphenyl)-2,2, butane, bis-(4-hydroxy-2,2-methylv phenyl)-2,2-propane, bis-(4 hydroxy 2 tertiary butyl phenyl-2,2-propane, bis-(Z-dihydroxynaphthyl)-rnethane, l,S dihydroXynaphthalene, and the like]. Such epoxy ethers are described in the patents to Bradley No. 2,500,600 and to Newey No. 2,553,718, and reference is made to these patents for descriptions of these resins and methods of preparing the same. Epoxy ether resins made by condensing epichlorhydrin and bis-(4-hydroxypheny1)- 2,2pr0pane (bis-phenol) are available commercially.

An important object of the present invention is to providea heat curable molding composition including an epoxy ether resin which composition will not set up or cure at room temperature (in other words, will be characterized by a long shelf life); which will not adhere, when set or cured, to the surface of thetmold (whether made of metal or other material) within which the molding operation is carried out; and which, when set or cured, will be characterized by extremely high electrical insulation resistance, highimpact resistance and low moisture absorption.

A specific object of this invention is toprovide azmolding composition of the nature indicated which when cured or set is characterized by distinct heat conductive properties.

'Anoth'er specific object of the invention is to provide a molding composition of the nature indicated modified so as to' render the set or cured. material electrically conductive, the electrical conductivitybeing'uniform through- Patented Dec. 4, 1956 6 ice invention comprise an epoxy resin (preferably made by reacting epichlorhydrin and bis-phenol) characterized by having the number designated in the above-noted structural formula as n falling within the range of from more than 0 up to about 20. It should be noted, in this connection, that the epoxide resins in question are mixtures of compounds each having the indicated structure, and that the number herein designated as n is the average of the integral numbers n which characterize each compound making up these mixtures.

If desired, the epoxy resin content of the molding composition may be distributed between several epoxy resins having n numbers of different. values, as long as the average of these numbers falls within the above disclosed range, due allowance being made for the proportion of the several epoxy resins.

The epoxy resin content of the molding compositions may range from 5 to 60% (by weight of the'molding compositions) or more;

The molding compositions of the present invention alson: Percent amine 0 25:5 2.5 10:2 12 6.25:2 20 1.5:1

At values of n falling between the tabulated values, the amount of amine is adjusted proportionally.

It is believed that when the above disclosed mixtures of epoxide resins and diaminodi'phenylmethane are heatcured, there takes place a cross linkage through reaction of the active hydrogens of the amines with the epoxide groups. The resulting compounds are of novel chemical structure, which explains the unusual properties of the heat-cured materials prepared according to the present invention.

The molding compositions of the present invention further include conventional fillers or pigments such as glass fibers or granules, asbestos, silica, perlite, biotite or mica, titanium dioxide, chrome yellow, zinc oxide, walnut shell, woodflour, carbon black, acetylene black or resinous material such" as nylon fiber. As disclosed hereinbelow, the incorporation oftacetylene black or like electrically conducting materials and of titanium dioxide or like heat conducting materials leads to the formation of resinous materials having unique properties.

The amount of fillers or pigments included with our molding compositions may be varied from 20% or less up to asinuchas depending upon the properties desired in the heat-cured material and upon the specific fillers and/or pigments employed. The particle size distribution of the fillers is often the factor determining the amount to be used for a particular purpose. sults have been obtained by using various fillers in the percentages (by weight of the molding composition) tabu- Good re- 3 to 5 minutes. The curing temperature ranges from 250 to 380 F. and usually falls within the range of from 280 to 350 F. The preferred range is from 300 to 315 F. The molding pressure ranges from to lated as follows: 5 to 2000 pounds per square inch, depending on the solvent Percent content (if any) of the molding composition, preheating Wood fl ur 40 75 (if any) of the molding composition, molding temperawalnut shell flour 4 75 ture, and other factors. Generally, enough pressure is Silica fl 50 9 used to form the molding composition into a solid or Nylon fib 35 95 10 dense product. At a temperature of from 250 to 350 F., Glass fib 04g the mold-mg .pressure will ordinarily range upwardly from Asbestos N 5 7 5 100 pounds per square inch. Tioz 2040 Any conventional molds may be used, such as the Wellkn .dtra f mlduuall It should be understood that the molding compositions 15 g g gg ig an er 0 S S y employed may comprise a mixture of several fillers and/or pig- Setting or wring in the mold takes place with the mentsexothermic generation of much less heat than is en- The mmstu'l'e content of e moldmg eomposltlons countered in the conventional molding of other thermoshould be less than 1% welght) Preferably less setting resins. Articles thicker than one inch or weighe ing more than 100 grams can be made without any In i i l n wlth the Preparanon 0f l trouble due to exothermic heat generation, Whereas if j ff should be noted that P' Y "j the same articles were made by conventional methods least equal 2 are Sends-i resins hev'mg from conventional molding compositions the temperature equal to 1 are liquids. When only solid epoxy resins would rise to 6 R or higher. e Included F mgredlents may hemmed m dry After molding has been completed, the molded articles form, as by milling on a two roller mull. However, are easily released from the molds (whether made of when tibrous fillers are lncluded, We prefier dlsselve metal or other material). In other words, there is no the resm m a sortable solvent (sucl 1 as acetone) an to trouble due to adhesion of the molded articles to the impregnate the fibrous filler with this solution before the mold surfaces. vmgredlents 9 e meldmg composmon or The molded articles prepared as disclosed hereinabove otherwise mrxed. It '18 of course, always poss1ble, even are characterized by highly desirable properties not here- Yvhen e so'hd leg'l'edlents are f m {final mold tofore obtainable in combination. Thus, moisture abmg mlxtmfei dlsselve e Fesms Y P sorption is less than A% and can be reduced to 0.1% and to mix the resulting solutions with the remaining or less. The electrical insulation resistance can be made (emf e B Tesults ere -W by F P to exceed 100,000 megohm-cm. The impact strength exmixing all the ingredients on atwo roller mill, the diamino ceeds 5 ft lbgjin, f notch (Izod) and can be made dlphenlflmethene bemg add-ed the Tesm bemg to exceed 5.0. When titanium dioxide (in an amount of solved in a solvent whenever fibrous fillers are employed. m re th n 50% by weight of the molding composition) when no solvent-15 used, y fibrous fillers are added is used as a filler, the molded articles are characterized gradually other e 40 by a remarkable heat conductivity coupled with high elecee Pe 'e makmg R molding trical insulation resistance and high impact strength. compositions, provision s made for removing such solw acetylene black (in amounts ranging from 8 to 0 mlnmg until the fie e eveporeted, 10% or more by weight of the molding composition) or y drylllg h solvenecfmtalmng molfimg eomposltlon other electrically conducting materials are used as fillers, l q e Preparatlon, by using molds hall-mg the molded products are electrically conducting, and this seltable breafhmg P f conductance is uniform throughout the articles. Such The 'resultlpng molding eompoeltlons are eIFeTeCteHZed uniform conductivity has heretofore never been obtained by an exceptionally llong, heretofore unobtamable shelf in molded resinous artic1es have e kept 9 mne memes end loeger Specific examples of molding compositions according Periods shewmg evldence efjeu'nng e e to the present invention are given hereinbelow. In these all l f Purposes: our moldmg f specific examples, we used epoxy resins prepared from may be considered as meeting any and all requirem epichlorhydrin and bisphenol. Epoxy resin No. 1 had that y P y be e e n" equal to 2.5. Epoxy resin No. 2 had 72 equal to sPlte of {011g shelf hves, our meldmg eemposl' about .3. Epoxy resin No. 3 has 71 equal to about 12. m Set icul'e q e when molded an elevated The diamino diphenylmethane is indicated in the follow- P fi The cure 111116 ranges from 15 Seconds (when ing table as D. A. D. P. M.; molding temperature was the molding composition is preheated) p to 10 nu s from 300 to 315 F.; molding pressure, from to (when particularly slow setting epoxy resins are molded 300 pounds per square inch; and molding time, from without any preheating). The average cure time is from 3 to 5 minutes:

Percent by Weight Comp. N0.

Resin D. A. D Resin Resin Nylon Glass Asbestos Silica Perlite #1 P. M. #3 Fiber Fiber Flour 30.0 6.67 13.33 10.0 33. 33 33.33 7.4 14.3 18.5 18.6 30.0 6.67 13.33 16.67 30 30.0 6.67 13.33 23. 33 23. 33 30.0 6.67 13.33 10.0 36.67 46.6 4.6 16.0 31.6 47. 69 4.76 47.67 18.0 2.0 22.5 6.0 10.0 52.0 Acetylene v Black 12.5 6.0 11.4 34.0 a0 16.6 27.6 6.2 13.6 30.6 16.9 30 5 Percent by Weight Physical Properties 0 N wlnt tif li HOAb I d M omp. o. a u eng 1 zo Insulation old Biotite T: Shell sorption, Impact Resistance, Shrinkage, or Mica Flour Percent Strength megohm inches per cm. inch Articles molded from composition No. 8 had a heat conductivity of 14 10'- cal./sec./cm. C. Articles molded from composition No. 9 had a uniform resistivity of 270 to 500 ohms-centimeter.

Results similar to those disclosed in the above specific examples were obtained when proceeding in exactly the same manner except for substituting, in place of resin No. 1, epoxy resins made with bis-phenol and having n equal, respectively, to 6 and to 12. The same applies 0 to other epoxy resins made with other dihydric phenols.

wherein R stands for the hydrocarbon radical of a dihydric phenol and n stands for a number ranging from more than 0 up to about 20, the said diamino compound being commingled with said epoxy resin in an amount ranging from V2 to 30% by weight of said resin.

2. A composition according to claim 1 in which the amount of said diamino compound is correlated with the magnitude of the said number represented by n" in said formula according to the following table n Percent diamino compound 0 -30 2.5 8-12 12 4.25-8.25 20 .52.5

the amount of said diamino compound being proportiona-lly adjusted for other values of n.

3. A composition according to claim 1 in which R stands for the hydrocarbon radical of bis-(4-hydroxyphenyl)-2,2-propane. i

4. A composition according to claim Icomprising titanium dioxide as a filler.

5. A composition according to claim 1 comprising acetylene black as a filler.

6. A method of making a molded resinous article which comprises providing a composition according to claim 1 and subjecting the said composition to heat and pressure.

7. A composition according to claim 2 in which R stands for the hydrocarbon radical of bis-(4-hydroxyphenyl) -2-2 propane.

8. A composition according to claim 2 comprising titanium dioxide as a filler.

9. A composition according to claim 2 comprising acetylene black as a filler.

10. A method according to claim 6 in which said pressure ranges from 10 to. 2000 pounds per square inch, said pressure being applied for from 15 seconds to 10 minutes, said pressure being applied at a temperature of from 250 to 380 F.

11. As a novel chemical composition, the end product of the process according to claim 6.

12. A composition according to claim 7 comprising titanium dioxide as a filler.

13. A composition according to claim 7 comprising acetylene black as a filler.

14. A composition according to claim 7 comprising a filler in an amount of from 20 to 95% of the total weight of said composition.

15. A composition according to claim 7 comprising two epoxy resins having "11 numbers of different values.

16. A method of making a molded resinous article characterized by heat conductivity which comprises providing a composition according to claim 8 and subjecting the said composition to heat and pressure.

17. A method of making a molded resinous article characterized by uniform electrical conductivity which comprises providing a composition according to claim 9 and subjecting said composition to heat and pressure.

18. A molded resinous article prepared according to the method of claim 16.

19. A molded resinous article prepared according to the method of claim 17.

20. An article according to claim 19 having an acetylene black content ranging upwardly from 8% by weight and comprising at least two epoxy resins having n numbers of different values.

21. A composition according to claim 1 comprising a filler in an amount of from 20 to of the total weight of said composition.

References Cited in the file of this patent UNITED STATES PATENTS 2,668,807 Greenlee Feb. 9, 1954 FOREIGN PATENTS 930,609 France Aug. 18, 1947 278,476 Switzerland Jan. 16, 1952 "OTHER REFERENCES The Chemistry of Commercial Plastics" by Wakeman, published 1947, by Reinhold Publishing Corp., page 545. 

1. A COMPOSITION OF MATTER COMPRISING PARA, PARA DIAMINO DIPHENYLMETHANE TOGETHER WITH AN EPOXY RESIN HAVING THE STRUCTURAL FORMULA 